1. Field of the Invention
Generally, the field of the present invention is multi-wavelength lasers. More particularly, the present invention relates to multi-wavelength semiconductor lasers with co-aligned output beams.
2. Background
Multi-wavelength laser systems have potential applications in many areas such as two-wavelength interferometry, laser spectroscopy, differential LIDAR, etc. For some of the applications, it is highly desirable to have the different wavelength beams to be co-aligned to within a few tens of micro-radian accuracy. In the semiconductor laser arts, providing an array of lasers with physically separated gain media for each wavelength is a common approach for multiple-wavelength operation. Dual-wavelength operation with a single semiconductor gain medium has also been achieved. However, these solutions resort to multi-component and complicated architectures to achieve dual or multi-wavelength output. Because of efficiency limitations, these devices tend to operate with low output powers. More importantly, some of these architectures do not provide a co-aligned multi-wavelength beam. Innovations herein are directed to overcoming the attendant problems of prior art architectures and other drawbacks.